The Division of Maternal-Fetal Medicine at the University of Alabama at Birmingham has a major interest in performing longitudinal population based studies on pregnancy outcome, specifically in the areas involving growth retardation, preterm delivery and hypertension leading to fecal and neonatal mortality and long term morbidity. We have extensive experience in performing clinical trials in these areas and have established a research unit and data handling capabilities which will enable us to participate in network clinical trials. Existing facilities, equipment, data management systems, recruitment resources, and personnel will be used to perform these selected network trials.